Not really. Steroids only accelerate muscle growth. In order for muscle growth to take place one must constantly advance in weightlifting through a progressive poundage scheme, eat a proper and strict diet containing proper proteins, fats and carbs plus get enough rest each night. Steroids are not a get ripped quickly scheme. The Rock was most likely already in immense shape before he started juicing (which by the way was for a movie which I see no harm in seeing as its his job).

That depends. If you have to use steroids to gain weight for a deadline. I see no reason not to. These guys are movie stars. They are required to drop 100 pounds in a 4 months and then then put it back on in a year.